Create transitional Service interfaces and switch tests and console to use them

Details

Description

As preparation of the change to use CXF instead of Spring MVC REST controllers this issue is to introduce transitional service interfaces (like as UserService).

The UserService interface should later be used in the core to provide the UserController and on the console to access the service remotely.

To make the transition easier the idea is to already introduce the interface upfront and change all tests and the console to use it. Before the switch the implementation of the interface will simply use the restTemplate under the covers.